Wheel marks and ruts in an area of mowed turf are unsightly and undesirable. During operation, the mower wheels, carrying the full weight of the mower, compress the grass blades downward towards the underlying soil. The compressed grass blades cannot regain their upright posture quickly enough to be cut by the mower blade, resulting in an uneven cut. As the strips of uncut grass spring up later, the turf can take on a streaked appearance. This is a particularly common problem when the grass is cut while damp or wet.
Many robotic mowers operate in a random pattern spending significantly more time traveling across a lawn than in the case of a human controlled mower. The robotic mower travels many times over some of the same areas of a lawn, and any features of the mower that are in contact with the turf can create observable wear, and in many cases, observable damage to the turf. Further, due to the constraints of battery operation, robotic mower cutting systems do not generally move as much air as conventional mowers. Without the air movement, grass that has been pushed down or laid over by the mower wheels is not drawn up into the mower cutting system.
As robotic mowers can operate without human oversight for extended periods of time, there are many instances where these products encounter obstacles and/or difficult terrain. In such instances, conventional robotic mower wheels do not provide enough traction for the mower to free itself from entrapment. Therefore, a human operator is required to locate the mower during its operation and free it manually.
Further, in order to maintain large areas, many robotic mowers must operate in all weather conditions, (i.e. rain or shine). When mowing in wet conditions, conventional tread wheels tend to collect cut grass in the form of a continuous band of material around the circumference. These bands or clumps of cut grass are known to build quite large over time, and can adversely affect the performance of the mower, and/or will separate from the wheel leaving an objectionable clump of material on the lawn surface.